多孔橡胶粉改性沥青降噪路面材料吸声特性试验研究

为研究多孔橡胶粉改性沥青路面降噪吸声特性，利用驻波管分别对30mm、40mm、50mm厚，孔隙率为20％的多孔橡胶粉改性沥青混合料试件和孔隙率为4％的普通沥青混合料试件进行了不同频率下吸声特性试验．分析了试件厚度、声波频率、材料、孔隙率、表面形态等对试件吸声特性的影响及材料吸声机理，并按1／3倍频测定了不同情况下材料的吸声系数．研究结果表明，随试件厚度的增加吸声系数增大；随入射声波频率增大，材料的吸声系数呈先增大后减小的趋势；多孔隙橡胶粉改性沥青混合料试件比普通沥青混合料试件吸声效果明显提高．因而证明，用多孔隙橡胶粉改性沥青混合料铺筑路面具有较好的降噪效果．

EXPERIMENTAL STUDY ON SOUND ABSORPTION CHARACTERISTICS OF POROUS CRUMB RUBBER MODIFIED ASPHALT PAVEMENT

With a view to studying sound absorption characteristics of porous crumb rubber modified asphalt pavement ,standing-wave tube experiments are conducted at different frequencies on the porous rubber modified asphalt mixture with 20% porosity and ordinary asphalt mixture with 4% porosity. Thicknesses of both mixtures are,respectively, 30 ram, 40 mm and 50 mm. The sound absorption mechanism of material as well as the influence of the sample＇s thickness ,sound frequency, material, porosity and surface pattern on sound absorption characteristics is analyzed. In the meantime, sound absorption coefficient is measured at 1/3 multiple frequency. It is shown that the sound absorption coefficient increases with the increase of the sample＇s thickness at however , with the increase of sound frequency,the sound absorption coefficient of material increases at the beginning and tends to decline thereafter. The porous crumb rubber modified asphalt mixture has much better absorption effect than ordinary asphalt mixture. Thus, it is proved that using porous crumb rubber modified asphalt mixture for pavement will produce better sound absorption and noise reduction effect.